1. Field of Invention
The present invention relates to a system for managing one or more radio modules in a wireless communication device, and more specifically, to a system and method for managing the operation of a dual-mode radio module integrated within a wireless communication device so as to avoid conflicts when connected to a short-range wireless network in a slave mode.
2. Description of Prior Art
Modern society has quickly adopted, and become reliant upon, handheld devices for wireless communication. For example, cellular telephones continue to proliferate in the global marketplace due to technological improvements in both the quality of the communication and the functionality of the devices. These wireless communication devices (WCDs) have become commonplace for both personal and business use, allowing users to transmit and receive voice, text and graphical data from a multitude of geographic locations. The communication networks utilized by these devices span different frequencies and cover different transmission distances, each having strengths desirable for various applications.
Cellular networks facilitate WCD communication over large geographic areas. These network technologies have commonly been divided by generations, starting in the late 1970s to early 1980s with first generation (1G) analog cellular telephones that provided baseline voice communication, to modern digital cellular telephones. GSM is an example of a widely employed 2G digital cellular network communicating in the 900 MHZ/1.8 GHZ bands in Europe and at 850 MHz and 1.9 GHZ in the United States. This network provides voice communication and also supports the transmission of textual data via the Short Messaging Service (SMS). SMS allows a WCD to transmit and receive text messages of up to 160 characters, while providing data transfer to packet networks, ISDN and POTS users at 9.6 Kbps. The Multimedia Messaging Service (MMS), an enhanced messaging system allowing for the transmission of sound, graphics and video files in addition to simple text, has also become available in certain devices. Soon emerging technologies such as Digital Video Broadcasting for Handheld Devices (DVB-H) will make streaming digital video, and other similar content, available via direct transmission to a WCD. While long-range communication networks like GSM are a well-accepted means for transmitting and receiving data, due to cost, traffic and legislative concerns, these networks may not be appropriate for all data applications.
Short-range wireless networks provide communication solutions that avoid some of the problems seen in large cellular networks. Bluetooth™ is an example of a short-range wireless technology quickly gaining acceptance in the marketplace. A 1 Mbps Bluetooth™ radio may transmit and receive data at a rate of 720 Kbps within a range of 10 meters, and may transmit up to 100 meters with additional power boosting. Enhanced data rate (EDR) technology also available may enable maximum asymmetric data rates of 1448 Kbps for a 2 Mbps connection and 2178 Kbps for a 3 Mbps connection. A user is not required to actively instigate a Bluetooth™ network. Instead, a plurality of devices within operating range of each other may automatically form a network group called a “piconet”. Any device may promote itself to the master of the piconet, allowing it to control data exchanges with up to seven “active” slaves and 255 “parked” slaves. Active slaves exchange data based on the clock timing of the master. Parked slaves monitor a beacon signal in order to stay synchronized with the master. These devices continually switch between various active communication and power saving modes in order to transmit data to other piconet members. In addition to Bluetooth™ other popular short-range wireless networks include WLAN (of which “Wi-Fi” local access points communicating in accordance with the IEEE 802.11 standard, is an example), WUSB, UWB, ZigBee (802.15.4, 802.15.4a), and UHF RFID. All of these wireless mediums have features and advantages that make them appropriate for various applications.
More recently, manufacturers have also begun to incorporate various resources for providing enhanced functionality in WCDs (e.g., components and software for performing close-proximity wireless information exchanges). Sensors and/or readers may be used to read visual or electronic information into a device. A transaction may involve a user holding their WCD in proximity to a target, aiming their WCD at an object (e.g., to take a picture) or sweeping the device over a printed tag or document. Machine-readable technologies such as radio frequency identification (RFID), Infra-red (IR) communication, optical character recognition (OCR) and various other types of visual, electronic and magnetic scanning are used to quickly input desired information into the WCD without the need for manual entry by a user.
Device manufacturers are continuing to incorporate as many of the previously indicated exemplary communication features as possible into wireless communication devices in an attempt to bring powerful, “do-all” devices to market. Devices incorporating long-range, short-range and machine readable communication resources also often include multiple wireless mediums or radio protocols for each category. A multitude of wireless media options may assist a WCD in quickly adjusting to its environment, for example, communicating both with a WLAN access point and a Bluetooth™ peripheral device, possibly (and probably) at the same time.
Given the large array communication features that may be compiled into a single device, it is foreseeable that a user will need to employ a WCD to its full potential when replacing other productivity related devices. For example, a user may use a multifunction WCD to replace traditional tools such as individual phones, facsimile machines, computers, storage media, etc. which tend to be more cumbersome to both integrate and transport. In at least one use scenario, a WCD may be communicating simultaneously over numerous different wireless mediums. A user may utilize multiple peripheral Bluetooth™ devices (e.g., a headset and a keyboard) while having a voice conversation over GSM and interacting with a WLAN access point in order to access the Internet. Problems may occur when these concurrent transactions cause interference with each other. Even if a communication medium does not have an identical operating frequency as another medium, a radio modem may cause extraneous interference to another medium. Further, it is possible for the combined effects of two or more simultaneously operating radios to create intermodulation effects to another bandwidth due to harmonic effects. These disturbances may cause errors resulting in the required retransmission of lost packets, and the overall degradation of performance for one or more communication mediums.
While a WCD may engage in wireless communication with a multitude of other devices concurrently, in some instances a resource constraint may arise where two or more of the peripheral devices are communicating using radio protocols that are implemented into a single radio modem in the WCD. Such a scenario may occur, for example, when both a Bluetooth™ device and a Wibree™ device are being used concurrently. Wibree™ is an open standard industry initiative extending local connectivity to small devices with technology that increases the growth potential in these market segments. Wibree™ technology may complement close range communication with Bluetooth™-like performance in the 0-10 m range with a data rate of 1 Mbps. Wibree™ is optimized for applications requiring extremely low power consumption, small size and low cost. Wibree™ may be implemented either as stand-alone chip or as Bluetooth™-Wibree™ dual-mode chip. More information can be found on the Wibree™ website: www.wibree.com. Due to the similarity of these two radio protocols, a WCD may only include one radio modem assigned to handle communication for both wireless mediums. One radio modem attempting to communicate with multiple devices using separate radio protocols, also known as a dual-mode radio modem, may experience communication errors due to the collision of messages from the peripheral devices. Wireless communication devices are usually scheduled only within their own radio protocol, and therefore, may be unaware that other simultaneous transactions may be occurring in a dual-mode radio modem over another radio protocol. Technology is now emerging to enable a WCD to schedule communications amongst a plurality of modems integrated within the same device, however, this control strategy may not necessarily benefit a dual-mode radio modem where the conflicts are not known at the operating system level, but only by the modem itself.
Further, scenarios may be foreseeable wherein a low-power wireless device acts as a master to other low-power slave devices while simultaneously communicating with a WCD. For example, a portable data collection device (e.g., a “smart” wristwatch) may be worn by someone performing physical activity to wirelessly receive (e.g., via Wibree™) physiological data from simple sensory devices located on various parts of the person's body. The sensor data may then be compiled and/or processed in the data collection device and wirelessly forwarded to a WCD for additional computation and/or viewing. Alternatively, the data collection and viewing responsibilities may be reversed, wherein the smart wristwatch acts as a viewer for information collected by the WCD. Regardless of the configuration, the more powerful WCD traditionally acts as a master to simpler devices in a wireless network. However, a low-power device acting as a master in its own network and a slave in another network, or “Scatternetting,” may not be supported in simpler communication mediums. In addition, low-power devices may not include the necessary processing power to allow for acting in different roles in multiple networks due to power and/or size limitations in these devices. As a result, a more complex device managing multiple active radio modules would necessarily be forced to operate in a slave mode, succumbing to the timing and control limitations of a simpler master.
In view of this problematic situation, what is therefore needed is a communication management system and strategy for a WCD that is acting in a slave role while communicating using a dual-mode radio module. The system should allow the WCD to maintain substantially concurrent communications over a plurality of radio modules while operating within the constraints established by a network-connected low-power device acting in a master role.